Laser welding and metal inert gas (MIG) welding is used in the manufacture of assemblies formed by welding thin metal sheets together. An example of this is the formation of cooling fins and radiators used in automotive and electronic applications, which are formed from thin metal sheets welded together along the perimeter of the sheets. Coolant passages defined by the metal sheets in the cooling fin and/or radiator may be formed and/or sealed by welding performed in the central portion of the fin and/or radiator. Weld quality is critical to the sealing of the cooling fin, radiator, and/or coolant passages formed therein.
Typically, the thin metal sheets are positioned together on a welding fixture, and retained to the welding fixture using mechanical clamps, during welding of the metal sheets to each other using a welding device such as a high energy laser, and electron beam/plasma, arc-welder, MIG welder, or other similar device. To weld the metal sheets to each other along their full perimeter, multiple steps are required, including welding along portions of the perimeter between and around the various clamps holding the metal sheets together, repositioning the clamps, and then welding in the remaining portions of the perimeter which were not accessible due to the initial positioning of the clamps. As such, multiple weld segments must be formed and connected with other weld segments to form a weld and/or seal about the entire perimeter of the metal sheets, and the welding device must be started and stopped for each weld segment and after repositioning of the clamps. The starting and stopping of the welding device and/or the overlapping of the weld segments can cause discontinuities in the weld which may affect weld quality and/or sealing integrity of the seal formed by the weld. Further, clamping, unclamping and re-clamping of the thin metal sheets during the welding process can cause distortion of the sheets, and shifts in positioning of the sheets relative to each other, resulting in warping due to thermal distortion and/or dimensional variability in the welded assembly.